Muffler



Jan. 21, 1941. B. c. KIRBY 2,229,576

MUFFLER Filed Aug. 7, 1939 2 Sheets-Sheet 1 XNVENTOR ATTORNEYS Jan. 21, 1941. Q K|RBY 2,229,576

MUFFLER 2 Sheets-Sheet 2 Filed Aug. 7, 1939 56772 arc djfz'ry INVENTOR ATTORNEYS Patented Jan. 21, 1941 UNITED STATES PATENT OFFICE Application August 7,

4 Claims.

This invention relates to improvements in mufflers for internal combustion engines and the like and especially is concerned with a novel muflier including means for withdrawing portions of exhaust gases from the mufller in a manner such that more facile operation of the muffler at least largely is promoted.

It is an object of the present invention to provide a novel muilier for use in treating exhaust gases from internal combustion engines and the like wherein means are provided for by-passing a portion of the exhaust gas effluent to promote the flow of exhaust gas through the muiller and also to facilitate the lowering of temperature of exhaust gases and the absorption of sound waves in the stream of exhaust gases resulting from explosion in the motor.

An advantage of the novel muffler according to this invention over existing types of mufflers is that in this novel muiiler there is at least a tendency for exhaust gases to be withdrawn from the exhaust manifold even when the motor is idling.

A feature of the novel mufller according to this invention is its comparative simplicity of construction both from the standpoint of structure and of assembly whereby the device is well suited to requirements of mass production with concomitant lowering of manufacturing costs.

Other objects, advantages and features of the new and improved muffler according to the present invention will be apparent to those skilled in this art during the course of the following description.

Regarded in certain of its broader aspects, the novel muiiler according to the instant invention comprises a casing having inlet and outlet pores traversed by exhaust gases; a pair of concentric tubes extending through said casing, the inner of said tubes being open at the ends whereby a stream of air can travel therethrough, the outer of said tubes communicating with the interior of said casing, and constricted formations behind openings in the innermost tube communicating with the outer tube whereby the stream of air passing through the inner tube draws exhaust gases from the chamber into the air stream.

In order to facilitate a fuller and more complete understanding of the present invention, a specific embodiment thereof herein illustrated will be hereinafter described, it being clearly understood, however, that the illustrated embodiment, although presently preferred, is provided solely by way of example of the practice of this invention and not by way of limitation thereof 1939, Serial No. 288,861

except insofar as the invention is recited in the subjoined claims.

Referring then to the drawings:

Figure 1 is substantially a vertical sectional View of the presently preferred embodiment of this invention,

Fig. 2 is essentially an enlarged view of a portion of the device shown in Fig. 1,

Fig. 3 is a vertical sectional view of Fig. 1, taken along the line 3-3 thereof, r

Fig. 4 is substantially a vertical sectional view of Fig. 1 taken along the line 4-4 thereof,

Fig. 5 is a detail elevational view of a part of the device shown in Fig. 1,

Fig. 6 is essentially a vertical sectional view of Fig. 2 taken along the line 6-6 thereof, and

Figs. '7, 8 and 9 are side elevational viewspartially in vertical section illustrating modified forms of the device according to this invention.

Reference is now made especially to Figs. 1 to 6 inclusive wherein the presently preferred embodiment of this invention best is illustrated. It will be noted that the muflier generally designated by the numeral comprises a hollow essentially cylindrical casing ll provided with end panels 12 having openings wherein are received the inlet and outlet conduits l3 and M respectively. The interior of the casing is subdivided by a plurality of partitions I5, I6, I1 and I8 extending transversely within the casing essentially as shown. It is to be noted that each of the partitions is provided with openings la, I551), I611, Ila and 18a. respectively. It is to be noted that the openings lid in the partition 15 are relatively larger and fewer in number than the openings l5b likewise formed therein. Further it is to be noted that both the distance between the partitions and the size of the openings formed therein diminishes as the distance from the inlet end of the casing increases. That is to say, the distance between the partitions I5 and I6 is greater than the distance between the partitions l6 and H, which in turn is greater than the distance be-- tween the partitions I1 and i8 and the openings I8a in the partition l8 are smaller than the openings lid in the partition ll which in turn are smaller than the openings |6a in the partitions I6 which likewise are smaller than the openings l5a and 15b in the partition IS.

A tube 20 mounted in registering openings in the casing ends I! extends through the interior of the casing essentially parallel to the axis thereof substantially as shown and is provided with a series of openings 20b formed therein over approximately two-thirds the length thereof whereby exhaust gases can pass through said openings into the interior of the tube 20 from the chambers defined by the casing end I2 and the partitions l5, l6 and II. It is'to be noted that no openings are provided in the tube in the portion extending through the parts of the casing between the partitions l1, I8 and the casing end l2. It is to be noted that one end of the tube 20 designated by the numeral 20a projects outwardly from the casing end and is bent downwardly for reasons which hereinafter more clearly will be apparent. A second tube generally designated by the numeral 25 provided with flared ends 25a is positioned coaxially within the tube 20 and the flared ends sealed thereto holding the tube in the spaced relationship illustrated.

The .tube 25 is provided in a portion thereof within the closed part of the tube 20 with a plurality of struck openings 26 arranged in a common plane perpendicular to .the axis of the tube, the struck portions of the tube being bent inwardly to constrict the channel defined by the tube and provide the obstructing formations 21 essentially as is illustrated in the drawings, particularly Figs. 2 and 6. It is to be understood that a stream or current of air passes through the tube generally designated by the numeral 25 in a direction such that the formations 21 are, with respect thereto, bent forwardly and inwardly.

In operation of this embodiment of the instant invention exhaust gases are received in the muffler casing from .the inlet tube I3 and disseminate into the chambers within the casing defined by the several partitions, the rate of travel of the exhaust gases of course being substantially diminished by the presence of the partitions and by the circuitous paths which they perforce must pursue. A portion of the exhaust gases entering the muffler will pass through the openings 20b in the tube 20 and int-o the space between the tubes 20 and 25, thereafter passing through the openings 26 into the interior of the inner tube from which they discharge through the end portion 20a of the tube 20 as indicated by the arrows. The discharge of exhaust gases in this manner is possible irrespective of whether or not a stream or current of air is passing through .the inner tube 25. However, when a stream or current of air is so passing through the tube, a partially evacuated or low pressure air pocket is formed in front of the constricted portion of the tube provided by the inwardly and forwardly bent formations 21. exhaust gases are drawn through the openings 26 into the interior of the inner tube 25 and from thence pass in the discharge stream through the end part 20a of the tube 20. It will be apparent from the foregoing that a portion of the exhaust gases normally discharged through the outlet I4 will be .by-passed and will be discharged through the bent end part 20a of the tube 20, thereby tending in a. measure 'to draw gases from the exhaust manifold of the engine through the inlet tube I3. Sound waves in the exhaust gases are deflected by the several partitions and, in at least a iarge measure thereby, absorb and dissipate whereby the discharge from the mufiler is essentially silent in the sense that lthe term is used in this art. Moreover, a continuous stream of air passing through the inner tube 25 serves to a measure at least to cool the mufiier acting in this respect as a heat exchanger, whereby the heat content of the mufil-er is diminished and Accordingly, the

the heat content of the air stream is increased.

Having thus described the preferred embodiment of the instant invention, reference is now made to Figs. 7, 8 and 9 wherein alternative or modified forms of the device according to this invention are illustrated. In Fig. 7 like reference numerals designate parts corresponding to those referred to in connection with the above described embodiment of this invention, it being noted that a casing intern-ally subdivided. by partitions and having an inlet and outlet conduit is provided with a tube 30 mounted therein and extending t-herethrough essentially as shown. The ends of .the tube 30 are essentially fixedly mounted in registering openings in the casing ends l2, it being noted that a major portion of the length of the tube is provided with openings 30a corresponding to the openings 20b formed in the tube 20 in the above described embodiment of this invenltion. The closed part of the tube 30 is constricted in the locality designated by the reference character 30b but the portion of the tube past the constricted part is of lesser diameter than of other parts of .the tube. An inner tube 3| flared at the end 3la thereof and sealed to the end of the tube 30 and to the casing end I2 extends coaxially within the tube 30 and is constricted to form a jet-like end portion 3Ib extending through the constricted portion 30b of the tube 30 whereby an air stream passing through tube 3| and discharging through said jet-like end portion draws exhaust gases from the interior of the muflier to discharge same in substantially the manner described above in connection with the preferred embodiment of this invention. It is to be noted that a plurality of tubes 30 radially spaced are provided in the muffler for facilitating discharge of exhaust gases as above described.

In Fig. 8 similarly an outer tube 35 is provided having openings 350. formed therein and having, instead of the constricted portion 301) as in the tube 30 above described, an inner tube 35b mounted in end portions of the tube 35 and being of substantially lesser diameter than said tube substantially as shown. A tube 36 having a flared end portion 36a is coaxially mounted within the tube 35 and is provided with a jet-like end portion 36b pointing into the inner tube 351) above described. It will be apparent that an air stream traveling through the tube 36 and discharging from the jet-like end portion 36b thereof will draw exhaust gases from the interior of the mufiler through the openings 35a of the outer tube 35 and will discharge same with the air stream through the inner tube 35b.

The embodiment of the instant invention illustrated in Fig. 9 is similar to the embodiment illustrated in Fig. 7 in that an outer tube 31 having openings 31a formed therein and constricted in a locality designated by the numeral 311) is mounted in themuffier ends l2. However, it is to be noted that the end portion 310 of the tube 31 is flared outwardly and that the inner tube 38 flared at one end 38a thereof for attachment to the tube 31 extends coaxially therethrough but terminates within the constricted portion 31b of the tube 31. It will be evident that an air stream traveling through-the tube 38 will draw exhaust gases from the interior of the mufiier through the openings 31a and discharge same mixed with the air stream through the flared end portion 31c of the tube 31.

Having thus described the present invention, what it is desired to secure by Letters Patent is:

1. An internal combustion engine muiiler, comprising a cylindrical body having an inlet at one end and an outlet at the opposite end, bailles in said body, a perforated tube extending longitudinally through the body and having open. ends forming a tight joint with the heads of the body, and a smaller tube passing concentrically through the perforated tube and having its ends closing the space between the two tubes, the inner tube having openings communicating with the space between the tubes.

2. An internal combustion engine mufller, comprising a cylindrical body having an inlet at one end and an outlet at the opposite end, baflles in said body, a perforated tube extending longitudinally through the body and having open ends forming a tight joint with the heads of the body, a smaller tube passing concentrically through the perforated tube and having its ends closing the space between the two tubes, the inner tube having openings communicating with the space between the tubes, and inwardly and rearwardly extending shields opposite each opening in the inner tube.

3. An internal combustion engine mufller, comprising a cylindrical body having an inlet at one body, a smaller tube passing concentrically through the perforated tube and having its ends reamed outwardly to form a tight joint with the perforated tube, the inner tube having struck-out portions forming openings and said struck-out portions extending rearwardly forming shields opposite each opening.

4. An internal combustion engine mufller, comprising a cylindrical body having an inlet at one end and an outlet at the opposite end, transverse perforated baflles in said body, a perforated tube extending longitudinally through the body and having open ends forming a tight joint with the heads of the body, a smaller tube passing concentrically through the perforated tube and having its ends reamed outwardly and forming a tight joint between the tubes, the inner tube having a circumferential struck-out portion forming openings and the struck-out portions extending rearwardly providing shields opposite each opening in the inner tube.

BERNARD C. KIRBY. 

